Semitendinosus Muscle Anatomy

Overview
Origin	Ischial tuberosity
Insertion	Medial surface of superior tibia
Action	Flexes knee Extends the hip Medially rotates the tibia when knee is flexed
Nerve	Sciatic (tibial, L5, S1, S2)
Artery	Inferior gluteal artery Perforating arteries

Contents

1. Location & Overview

2. Origin & Insertion

3. Actions & Function

4. Innervation

5. Blood Supply

6. References

Location & Overview

The semitendinosus muscle is a superficial muscle located at the posterior and medial aspect of the thigh. It is more superficial than the semimembranosus (meaning it is located on top of it). The attachments of the semitendinosus and semimembranosus also have quite close attachment points. The semitendinosus is one of the three hamstring muscles located at the posterior thigh. The other two hamstring muscles are the semimembranosus and the biceps femoris muscles. The semitendinosus is located somewhat between the semimembranosus and the biceps femoris muscles ^[1].

Here we can see the semitendinosus muscle in isolation.

Here we can see the semitendinosus muscle’s distal tendon in isolation.

Here we can see the semitendinosus muscle from a superficial view.

Here we can see the semitendinosus muscle and the rest of the hamstring muscles from a superficial view.

Origin & Insertion

The semitendinosus originates at the superior portion of the iscial tuberosity. It then works its way down the posterior portion of the thigh across the medial portion where it then inserts below the knee on the medial surface of the superior part of the tibia ^[2]. This insertion is part of the group of tendons called the ‘pes anserinus’ which insert in this region. The pes anserinus is comprised of the tendons of the semitendinosus, sartorius and gracilis muscles ^[3].

Here we can see the origin of the semitendinosus muscle highlighted in red. It originates at the ischial tuberosity.

Here we can see the insertion of the semitendinosus muscle highlighted in blue. It inserts at the medial surface of superior tibia.

Actions & Function

The semitendinosus muscle is able to flex the knee. It can extend the hip. The semitendinosus can also assit in medially rotating the tibia on femur when the knee is flexed ^[4] ^[5].

Innervation

The semitendinosus muscle is innervated by the sciatic nerve (tibial, L5, S1, S2) ^[6].

Blood Supply

Blood is supplied by the inferior gluteal artery and perforating arteries ^[7].

Want some flashcards to help you remember this information? Then click the link below:
Semitendinosus Muscle Flashcards

References

References
↑1, ↑3	Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.
↑2, ↑4	Rodgers CD, Raja A. Anatomy, Bony Pelvis and Lower Limb, Hamstring Muscle. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546688/
↑5, ↑6	Afonso J, Rocha-Rodrigues S, Clemente FM, et al. The Hamstrings: Anatomic and Physiologic Variations and Their Potential Relationships With Injury Risk. Front Physiol. 2021;12:694604. Published 2021 Jul 7. doi:10.3389/fphys.2021.694604
↑7	Tomaszewski KA, Henry BM, Vikse J, Pękala P, Roy J, Svensen M, Guay D, Hsieh WC, Loukas M, Walocha JA. Variations in the origin of the deep femoral artery: A meta-analysis. Clin Anat. 2017 Jan;30(1):106-113. doi: 10.1002/ca.22691. Epub 2016 Feb 2. PMID: 26780216.